This invention relates to load lifting accessories, and particularly relates to load lifting accessories which are used with manual shovels for handling heavy loads such as snow, sand and soil. The load lifting accessory of the present invention is designed in such a manner that when it is in use with the manual shovel, the user is relieved of severe vertebral and back muscle strains which are associated with shovelling heavy loads. Furthermore, the load lifting accessory of the present invention is such that it may be easily removably attached to the shaft of the manual shovel so as to provide the user the flexibility to transfer the load lifting accessory to the shaft of any conventional manual shovel.
Shovelling heavy loads such as snow, sand and soil has been one of the leading causes of back strain injuries. In fact, gardeners and other individuals who are required to shovel heavy loads on the job are reported to be the most susceptible victims to such injuries. For many others, shovelling snow throughout the winter months often results in vertebral and muscle strains.
Indeed, shovelling snow has been compared to weightlifting by some kinesiologists. It requires a lot of exertion and it is a multi-joint movement exercise. A variety of muscles are used during the activity, both large and small muscles-large muscles such as leg muscles and small muscles such as those found in the region of the lower back. The small muscles are particularly prone to strain injuries because these small muscle groups are not used as often as the large leg muscles. For those persons who are naturally weak or for those who don""t usually get much exercise, shovelling heavy loads may be a health risk.
A conventional manual shovel is, in fact, not a very efficient tool to lift heavy loads since a relatively large effort needs to be exerted by the user to overcome the resistance of each load. Generally, the user grips the shaft of the shovel with one hand at a point which is relatively low along the length of the shaft, and uses his other hand to effectively lever the shaft about that point. A conventional manual shovel is a typical example of a third class lever. The effort is applied by the one hand which is positioned near the load, and the fulcrum is situated at the other hand which is distal from the blade of the shovel. Physiologically, the spinal vertebrae and the associated back muscles act as a cantilever to resist the weight of the load in each shovelling motion. Since the back of the user is typically bent forward to load and lift the shovel, the whole weight of his torso, shoulders, arms and head adds additional strain to his back. The spine is stressed in compression and the muscles in tension to resist the bending of the back, and thus often leads to fatigue, soreness, and injuries.
Although powered shovels may be employed as an alternative, they are considered to be too expensive for many consumers. Furthermore, most powered shovels are difficult for storage and are not portable. In areas where access is limited, shovelling with a powered shovel may also pose difficulties since most powered shovels are bulky and heavy to manoeuver.
The present inventor herein has provided a load lifting accessory which is adapted to be affixed to the shaft of a conventional manual shovel. The load lifting accessory of the present invention is simple, economical, portable, lightweight and compact. In addition, the load lifting accessory of the present invention is such that it may be easily removably attached to the shaft of the manual shovel so as to provide the user the flexibility to transfer the load lifting accessory to the shaft of any conventional manual shovel. Most importantly, the load lifting accessory of the present invention is designed in such a manner that when it is in use with the manual shovel, the user is relieved of severe vertebral and back muscle strains which are associated with shovelling heavy loads.
The load lifting accessory of the present invention generally comprises a bracket, a support arm and a retractor arm. The bracket is adapted to embrace the underside of the shaft of the shovel when the shovel is oriented in a normal shovelling position in such a manner that the region of the midpoint of the underside of the shaft of the shovel is rested against the inner surface of the bracket. The support arm is attached to the outer surface of the bracket by attachment means which permits pivotal movement of the support arm. When the shovel is in a non-operative position, the support arm is contiguous to the outer surface of the bracket. However, when the shovel is in an operative position, the support arm extends substantially vertically downwardly from the bracket to the ground.
When the load lifting accessory of the present invention is affixed to the shaft of the shovel, the conventional shovel becomes a first class lever, thus making the accessorized conventional shovel substantially more effective in overcoming large resistance since a relatively small effort is required for the operation of a first class lever. Here, the support arm of the load lifting accessory of the present invention operates as the fulcrum while the effort is applied by both hands of the user. Normally, lifting forces are applied by the user to the shaft of the conventional shovel having no load lifting accessory. However, with the implementation of the load lifting accessory to the conventional shovel, lifting forces are no longer required. Instead, the user needs only to apply downward forces to the shaft of the shovel since the support arm of the load lifting accessory provides the necessary upward lifting forces. To that end, the user may easily shovel heavy loads without bending his back, thus greatly reducing the usual spinal and back muscle strains and stresses.
Several prior art patents are noted, which relate particularly to shovelling tools and the like utilizing fulcrum type aids. They include the following:
BRUNO U.S. Pat. No. 4,130,953 issued Dec. 26, 1978;
KRUG U.S. Pat. No. 5,863,084 issued Jan. 26, 1999;
YANG U.S. Pat. No. 4,537,433 issued Aug. 27, 1985;
VROEGINDEWEY U.S. Pat. No. 5,669,651 issued Sep. 23, 1997;
LIGHTHIZER U.S. Pat. No. 4,722,512 issued Feb. 2, 1988;
PRATT U.S. Pat. No. 3,119,596 issued Jan. 28, 1964; and
CONANT U.S. Pat. No. 3,035,816 issued May 22, 1962.
Several other patents which relate more to the load lifting accessory, include the following:
EVERTSEN U.S. Pat. No. 4,881,332 issued Nov. 21, 1989 teaches an elongate, ground contacting member which is pivotally attached to an intermediate point along the handle of the shovel or similar tools. The elongate, ground contacting member has attachment means which permits rotation of the ground contacting member about its own axis. When the shovel is loaded, it is raised to the hip level of the user by drawing back and lowering the end of the handle opposite the shovel head while the ground contacting member acts as a fulcrum between the load and the user""s applied force. The shovel head is then permitted to move sideways to deposit the load where desired. There are no means to stabilize the uncontrolled swinging of the elongate, ground contacting member when it is extended to the ground, and furthermore the device taught in this patent is not readily detachable from the primary tool.
In U.S. Pat. No. 4,198,090 issued Apr. 15, 1980 to GUTMAN, the inventor has provided a shovel which utilizes an adjustable type fulcrum member in combination with an adjustable hand gripping member for purposes of easing the shovelling of a load. The adjustable lever mechanism is releasably secured and movably displaceable in a direction substantially normal to the shaft of the shovel so as to provide an adjustable height above a base surface when the blade of the shovel is in contact with the base surface. The adjustable grip mechanism is releasably secured and movably displaceable with respect to the shaft and extends above such a shaft so as to provide the user with a secondary gripping portion.
In another U.S. Pat. No. 5,487,530 issued Jan. 30, 1996, the inventor McCULLOUGH teaches a shovelling aid which comprises an elongated bracing member wherein the elongated bracing member is releasably attachable to the shaft of the shovel at a selected position away from the blade of the shovel. The bracing member comprises a pipe section which has upper and lower openings on opposed sides. A sleeve which is coupled to the pipe section in the upper openings receives the shaft of the shovel at a predetermined angle relative to the pipe section.
U.S. Pat. No. 5,732,933 issued Mar. 31, 1998 to CHAMPI teaches a lifting implement for a conventional snow shovel or like tools. The lifting implement comprises an elongate lever arm having first and second ends. The first end of the lever arm is pivotally attached to the shovel handle while the second end of the lever arm terminates in a curved fork and spans by a foot-engaging cross-bar. The curved fork serves as the fulcrum for the application of downward foot pressure by the user on the cross-bar.
Finally, SAMUELSON U.S. Pat. No. 5,918,921 issued Jul. 6, 1999 teaches a levered shovel for moving snow which comprises a wheel assembly for contacting a horizontal surface and wherein the wheel assembly depends from the shaft of the shovel. The wheel assembly comprises either an axle fork, an axle rotatively mounted to the axle fork, and a pair of wheels attached to the axle or an inverted T-shaped member with its transverse portion serving as its axle to which a pair of wheels are rotatively attached. Furthermore, the shaft of the shovel comprises a hand assembly which is disposed on the end of the shaft distal from the blade. The handle assembly has a lower transverse member for gripping and extends laterally from both sides of the rearmost end of the shaft. Additionally, the hand assembly includes an extender which elevates the gripping point of the user on the handle such that the user may maintain a relatively upright posture.
In a first general embodiment, the present invention provides a load lifting accessory which is adapted to be affixed to the shaft of a shovel. The load lifting accessory of the present invention comprises a bracket, a support arm, an extension member and a retractor arm.
The bracket has inner and outer surfaces, first and second ends, and first and second side edges.
The bracket is adapted to embrace the underside of the shaft of a shovel when the shovel is oriented in a normal shovelling position, and is such that the underside of the shaft of the shovel, in the region of the midpoint thereof, is rested against the inner surface of the bracket.
Furthermore, the bracket is attached to the shaft of the shovel by attachment means. Still further, the outer surface of the bracket has a support arm attached thereto by attachment means which permits pivotal movement of the support arm.
The support arm has top and bottom ends, and first and second side edges.
When the support arm is in a first, non-operative position, the support arm is contiguous to the outer surface of the bracket at the second end. However, when the support arm is in a second, operative position, the support arm extends substantially vertically downwardly from the bracket to the ground.
The extension member has first and second ends. The second end of the extension member is secured against the outer surface of the bracket in the region of one of the first and second side edges.
The retractor arm has first and second ends. The first end of the retractor arm is pivotally and slidably attached to the first end of the extension member whereas the second end of the retractor arm is pivotally attached to one of the first and second side edges of the support arm at a point which is intermediate the first and second ends thereof.
Typically, the bracket has a U-shaped cross section so as to embrace the underside of a cylindrical shaft of a shovel.
The bracket is attached to the shaft of the shovel by attachment means which is chosen from the group of attachment means consisting of clamps, straps and buckles, and bolts.
In keeping with the present invention, the first end of the retractor arm is pivotally and slidably attached to the first end of the extension member by a pivotal means which has a passage formed therein so as to permit the retractor arm to extend therethrough.
Typically, but not necessarily, the support arm is formed from materials chosen from the group of materials consisting of wood, metals and plastics.
The support arm has two portions in which the two portions are telescopically fitted one over the other so as to permit the length of the support arm to be adjusted.
In a particular variation, the support arm is offset forwardly.
Typically, but not necessarily, the load lifting accessory which is described above may further comprise a foot member. The foot member is removably attached to the bottom end of the support arm.
In a second general embodiment of the present invention, there is provided a load lifting accessory which is adapted to be affixed to the shaft of a shovel. The second embodiment of the load lifting accessory of the present invention comprises a bracket, a support arm, an actuator, and a retractor arm.
The bracket has inner and outer surfaces, first and second ends, and first and second side edges.
When the shovel is oriented in a normal shovelling position, the bracket is adapted to embrace the underside of the shaft of the shovel in such a manner that the underside of the shaft of the shovel, in the region of the midpoint thereof, is rested against the inner surface of the bracket.
The bracket is attached to the shaft of the shovel by attachment means. Furthermore, the outer surface of the bracket has a support arm attached thereto by attachment means which permits pivotal movement of the support arm.
The support arm has top and bottom ends, and first and second side edges.
When the support arm is in a first, non-operative position, the support arm is contiguous to the outer surface of the bracket at the second end. However, when the support arm is in a second, operative position, the support arm extends substantially vertically downwardly from the bracket to the ground.
The actuator has first and second ends, and first and second sides at the same side of the load lifting accessory as the first and second side edges of the support arm.
The first end of the actuator is pivotally attached to the outer surface of the bracket, in the region between the first end of the bracket and the attachment point of the support arm.
The retractor arm has first and second ends. The first end of the retractor arm is pivotally attached to one of the first and second sides of the actuator, in the region between the first end and the midpoint thereof, whereas the second end of the retractor arm is pivotally attached to one of the respective first and second side edges of the support arm at a point which is intermediate the first and second ends thereof.
Typically, the bracket has a U-shaped cross section so as to embrace the underside of a cylindrical shaft of a shovel.
The bracket is attached to the shaft of the shovel by attachment means chosen from the group of attachment means consisting of clamps, straps and buckles, and bolts.
Typically, but not necessarily, the support arm is formed from materials chosen from the group of materials consisting of wood, metals and plastics.
The support arm has two portions and is such that the two portions are telescopically fitted one over the other so as to permit the length of the support arm to be adjusted.
In a particular variation of the second embodiment, the support arm is offset forwardly.
In keeping with the present invention, the load lifting accessory may further comprise a foot member. The foot member is removably attached to the bottom end of the support arm.